This invention relates to a instant film unit advancing apparatus used for an instant camera or an instant printer to perform a diffusion transfer development while advancing the film unit.
Cameras or video printers using a mono-sheet type instant film unit as a recording media are equipped with a film unit advancing apparatus to thrust the film unit out of a film unit pack after exposing the film. The film unit advancing apparatus includes a picking claw to pick the film unit to thrust it out of the film unit pack through an exit slot, a pair of spreading rollers for spreading a developing liquid by pressing the film unit while advancing it to discharge from the camera or video printer and a driving mechanism therefor, which are driven by a common motor. Instant film unit is used for the camera or printer usually in the form of a film pack which holds a plurality of film units arranged in stacked relation therein. The camera or the printer has a film pack loading chamber around which a pair of spreading rollers, driving mechanism therefor and a picking claw driving mechanism are disposed. Japanese laid-open patent application 92/194832 (tokkai-hei 4-194832) shows an instant camera in which a pair of spreading rollers disposed above the film pack loading chamber and a spreading roller driving mechanism and a picking claw driving mechanism are disposed along the side of the chamber.
Japanese laid-open patent application 95/24553 (tokkai-hei 7-248553) shows a picking claw moved by a cam plate to move which is rotated by a common motor to drive a pair of spreading rollers. The picking claw is supported by a slide plate having an integrally formed cam follower. The cam follower engages a periphery of the cam plate so that the picking claw is moved as the cam plate rotates. A predetermined stroke movement of the picking claw thrusts a film unit to a bite of the rotating spreading rollers. Then the film unit is further advanced by the pair of rotating spreading rollers while developing liquid in a container of the film unit is discharged and spread by the roller pressure. Meanwhile, the cam keeps on rotating to return the picking claw to its home position. One cycle of a sequential process that film unit is picked up at its trailing end by the picking claw, thrust out into the bite of a pair of spreading rollers, discharged out of camera and the picking claw is returned to the home position is made by one rotation of the cam plate. Upon detecting the one rotation, the motor is stopped.
This mechanism requires relatively large cam plate because the difference between the largest diameter and the smallest diameter of the cam plate has to match the stroke of the picking claw, which makes it difficult to reduce the size of film unit advancing apparatus. The mechanism also requires an appropriate number of the spreading roller rotation during one rotation of the cam plate so as to discharge the film unit out of the camera or the printer, which may cause failure of discharging film unit if a slip arises between the spreading rollers and the film unit.
The spreading roller has extended small diameter portions (journal portions) both at its end to be supported by bearings, which makes total length of the spreading rollers wider than the width of film pack. This is another cause of making it difficult to reduce the size of camera or printer using an instant film unit.
An object of the invention is to provide an instant film unit advancing apparatus used in camera or printer of which size is reduced by designing new dispositions of a roller driving mechanism and/or a picking claw mechanism, particularly by improvements in terms of preventing components for the mechanism from being located beyond the width of the film unit pack. Another object of the invention is to provide a compact picking claw mechanism which does not use a large cam plate as in conventional technology to finish one cycle of picking claw sequence, i.e. from starting advancing a film unit by picking an trailing edge thereof through returning to home position. Further object of the invention is to provide a film unit advancing apparatus which can avoid failure of discharging film unit out of camera or printer when a slip arises between spreading rollers and the film unit.
Yet further object of the invention is to provide a method for operating the improved film unit advancing apparatus.
To accomplish those objects, the following each elements is used alone or in combination of some elements for the instant film unit advancing apparatus of the invention.
1. One way transmission device for transmitting rotational force from a motor to a pair of spreading roller only when the motor rotates forwardly and not transmitting when the motor rotates reversely.
2. Keep-positioning means for keeping the picking claw in the same position despite of rotation of the motor.
3. Reciprocating means for reciprocating a picking claw between a home position and an advanced and waiting position, wherein the reciprocating means can return the picking claw from the advanced and waiting position to the home position by making use of reverse rotation of the motor.
4. Each of a pair of spreading rollers is rotatably supported on its surface by roller supporting means.
5. A driving power source unit for driving the pair of spreading rollers and picking claw constituted by the motor and the reducing gear train mounted on a plurality of shaft one of which is connected to a output shaft of the motor, wherein all the shafts of the driving power source unit is arranged parallel to the pair of spreading rollers.
6. The picking claw is slidably mounted behind a rear plate of the base frame which is mounted inside the film unit loading chamber for positioning the film unit pack.
7. Forward and reverse rotation to advance the film unit and return the picking claw is controlled by a timer.
Preferred embodiments of the invention are as follows.
An instant film unit advancing apparatus for advancing a film unit after exposure for developing and discharging outside, comprises a loading chamber for loading a film unit pack; a pair of spreading rollers driven by a motor for developing and advancing an exposed film unit; a picking claw for thrusting the exposed film unit to a bite of the pair of spreading roller (by picking a trailing edge of the exposed film unit); an one way transmission device for transmitting rotational force from the motor to the pair of spreading roller only when the motor rotates forwardly and not transmitting when the motor rotates reversely; and a reciprocating means for reciprocating the picking claw between a home position and an advanced and waiting position, wherein the reciprocating means includes a shifting means for shifting the picking claw between the home position and the advanced and waiting position and a keep-positioning means for keeping the picking claw in the same position despite of rotation of the motor. Preferably the shifting means includes a motor driven cam shaft having a spiral cam groove on the periphery and a interconnecting lever which has a cam follower on one end engaging the spiral cam groove so that the interconnecting lever can swing as the cam shaft rotates to shift the picking claw by a predetermined stroke.
An instant film unit advancing apparatus for advancing a film unit after exposure for developing and discharging outside, comprises a loading chamber for loading a film unit pack; a pair of spreading rollers driven by a motor for developing and advancing an exposed film unit; a picking claw for thrusting the exposed film unit to a bite of the pair of spreading roller (by picking a trailing edge of the exposed film unit); and a reciprocating means for reciprocating the picking claw between a home position and an advanced and waiting position, wherein the reciprocating means can return the picking claw from the advanced and waiting position to the home position by making use of reverse rotation of the motor.
An instant film unit advancing apparatus for advancing a film unit after exposure for developing and discharging outside, comprises a loading chamber for loading a film unit pack; a base frame mounted inside the loading chamber for positioning the film unit pack; a picking claw for thrusting the exposed film unit to a bite of the pair of spreading roller (by picking a trailing edge of the exposed film unit); and a pair of spreading rollers driven by a motor for developing and advancing an exposed film unit, wherein each of the pair of spreading rollers is rotatably supported on its surface by a roller supporting means.
An instant film unit advancing apparatus for advancing a film unit after exposure for developing and discharging outside, comprises a loading chamber for loading a film unit pack; a base frame mounted inside the loading chamber for positioning the film unit pack; a picking claw for thrusting the exposed film unit to a bite of the pair of spreading roller; a pair of spreading rollers for developing and advancing an exposed film unit; and a driving power source unit for driving the pair of spreading rollers and picking claw constituted by the motor and the reducing gear train mounted on a plurality of shaft one of which is connected to a output shaft of the motor, wherein all the shafts of the driving power source unit is arranged parallel to the pair of spreading rollers. Preferably the picking claw is slidably mounted behind a rear plate of the base frame.
An instant film unit advancing apparatus for advancing a film unit after exposure for developing and discharging outside, comprises a loading chamber for loading a film unit pack; a base frame mounted inside the loading chamber for positioning the film unit pack; a picking claw driven by a cam shaft for thrusting the exposed film unit to a bite of a pair of spreading roller; and a driving unit including a driving power source unit, a pair of spreading rollers, intermediate gears for transmitting a rotational force from the driving power source unit to the pair of spreading rollers and the cam shaft, wherein the driving unit is located within a space defined by a top wall of a cassette of the film unit pack where a film unit exit slot is formed and both side plates of the base frame.
A method of advancing an instant film unit for developing and discharging outside, comprises steps of starting a motor rotating forwardly after a film unit is exposed in order to rotate a pair of rollers and a cam shaft to move a picking claw; starting timer system at the same time where a first predetermined time period is set, generating motor-stop signal when the first predetermined time period passes; starting the motor rotating reversely to return the picking claw to home position while keeping stopping the pair of rollers; starting timer system at the same time where a second predetermined time period is set; and generating motor-stop signal when the second predetermined time period passes.